5 points for doing the right question, 0 points for not doing it, 2 points for doing the wrong question, and 58 points.
Then: 5*(20-X)-2X=58.
The solution is X=6.
So, Xiaohua made six mistakes.
(2) Solution: Suppose the kitten made a mistake in question X, and the question she didn't do was also X, then the question she did correctly was 20-2X.
5*(20-2X)-2X=64
The solution is X=3.
The kitten made three mistakes, three didn't, and the rest were all right.
So the kitten got it right. Question 20-3-3= 14.
Primary school students in grade six have learned to set unknowns to solve equations, so it is understandable to set unknowns.
I hope I can help you.